Evolution of the eye

The evolution of the eye has attracted significant study, with the eye distinctively exemplifying an analogous organ present in a wide variety of animal forms. Complex, image-forming eyes have evolved independently some 50 to 100 times

Complex eyes appear to have first evolved within a few million years, in the rapid burst of evolution known as the Cambrian explosion. No evidence of eyes before the Cambrian has survived, but a wide range of diversity is evident in the Middle Cambrian Burgess shale, and in the slightly older Emu Bay Shale.[2] Eyes show a wide range of adaptations to meet the requirements of the organisms which bear them. Eyes vary in their visual acuity, the range of wavelengths they can detect, their sensitivity in low light, their ability to detect motion or to resolve objects, and whether they can discriminate colours.